Currency has been replaced by a point system based on one's total contributions to society. Points determine one's value allowance of luxuries, but all necessary commodities are provided regardless of point level. A certain requisite level of points is required to hold various positions of responsibility. Points can also be spent for the privilege of breaking various rules or social expectations, or for taking away points from others (thus taking away their right to hold a position of responsibility, as well as their privileges) at a costly rate of conversion. The assumption is that even if people accrue points in order to victimize others or spend them on rule breaking privileges, the conversion rate will still require them to perform net positive contributions to society in the process.

On further reflection, I suppose this isn't that different from the system we already have, but it might be able to beat it if you suppose that we can do better than the free market at judging people's overall contribution to society.